Federal Register / Vol. 72, No. 76 / Friday, April 20, 2007 / Proposed Rules 19823 

TABLE 1.—PREVIOUS ISSUES OF SERVICE BULLETINS

Model Airbus Service 

Bulletin Revision level Date 

A300 airplanes ...................................................................................... A300–53–0246 03 April 11, 2001. 

A300–53–0246 04 November 12, 2002. 

A300–53–0246 05 January 19, 2004. 

A300 B4–601, B4–603, B4–620, B4–622, B4–605R, B4–622R, F4–

605R, F4–622R, and C4–605R Variant F airplanes.

A300–53–6029 05 April 11, 2001. 

A300–53–6029 06 November 12, 2002. 

A300–53–6029 07 January 19, 2004. 

Alternative Methods of Compliance (AMOCs) 

(s)(1) The Manager, International Branch, 

ANM–116, has the authority to approve 

AMOCs for this AD, if requested in 

accordance with the procedures found in 14 

CFR 39.19. 

(2) Before using any AMOC approved in 

accordance with § 39.19 on any airplane to 

which the AMOC applies, notify the 

appropriate principal inspector in the FAA 

Flight Standards Certificate Holding District 

Office. 

(3) AMOCs approved previously in 

accordance with AD 2003–06–04 are 

approved as AMOCs with this AD until 

paragraph (j) of this AD is accomplished. 

Related Information 

(t) French airworthiness directive F–2006–

016, dated January 18, 2006, also addresses 

the subject of this AD. 

Issued in Renton, Washington, on April 12, 

2007. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. E7–7516 Filed 4–19–07; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2007–27927; Directorate 

Identifier 2006–NM–182–AD] 

RIN 2120–AA64 

Airworthiness Directives; Airbus Model 

A300 Series Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for all 

Airbus A300 series airplanes. This 

proposed AD would require revising the 

Airworthiness Limitations Section of 

the Instructions for Continued 

Airworthiness to incorporate new 

limitations for fuel tank systems. This 

proposed AD results from fuel system 

reviews conducted by the manufacturer. 

We are proposing this AD to prevent the 

potential of ignition sources inside fuel 

tanks, which, in combination with 

flammable fuel vapors caused by latent 

failures, alterations, repairs, or 

maintenance actions, could result in 

fuel tank explosions and consequent 

loss of the airplane. 

DATES: We must receive comments on 

this proposed AD by May 21, 2007. 

ADDRESSES: Use one of the following 

addresses to submit comments on this 

proposed AD. 

• DOT Docket Web site: Go to 

http://dms.dot.gov and follow the 

instructions for sending your comments 

electronically. 

• Government-wide rulemaking Web 

site: Go to http://www.regulations.gov 

and follow the instructions for sending 

your comments electronically. 

• Mail: Docket Management Facility, 

U.S. Department of Transportation, 400 

Seventh Street, SW., Nassif Building, 

Room PL–401, Washington, DC 20590. 

• Fax: (202) 493–2251. 

• Hand Delivery: Room PL–401 on 

the plaza level of the Nassif Building, 

400 Seventh Street, SW., Washington, 

DC, between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

Contact Airbus, 1 Rond Point Maurice 

Bellonte, 31707 Blagnac Cedex, France, 

for service information identified in this 

proposed AD. 

FOR FURTHER INFORMATION CONTACT: Tom 

Stafford, Aerospace Engineer, 

International Branch, ANM–116, FAA, 

Transport Airplane Directorate, 1601 

Lind Avenue, SW., Renton, Washington 

98057–3356; telephone (425) 227–1622; 

fax (425) 227–1149. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite you to submit any relevant 

written data, views, or arguments 

regarding this proposed AD. Send your 

comments to an address listed in the 

ADDRESSES section. Include the docket 

number ‘‘FAA–2007–27927; Directorate 

Identifier 2006–NM–182–AD’’ at the 

beginning of your comments. We 

specifically invite comments on the 

overall regulatory, economic, 

environmental, and energy aspects of 

the proposed AD. We will consider all 

comments received by the closing date 

and may amend the proposed AD in 

light of those comments. 

We will post all comments we 

receive, without change, to http:// 

dms.dot.gov, including any personal 

information you provide. We will also 

post a report summarizing each 

substantive verbal contact with FAA 

personnel concerning this proposed AD. 

Using the search function of that Web 

site, anyone can find and read the 

comments in any of our dockets, 

including the name of the individual 

who sent the comment (or signed the 

comment on behalf of an association, 

business, labor union, etc.). You may 

review the DOT’s complete Privacy Act 

Statement in the Federal Register 

published on April 11, 2000 (65 FR 

19477–78), or you may visit http:// 

dms.dot.gov. 

Examining the Docket 

You may examine the AD docket on 

the Internet at http://dms.dot.gov, or in 

person at the Docket Management 

Facility office between 9 a.m. and 5 

p.m., Monday through Friday, except 

Federal holidays. The Docket 

Management Facility office (telephone 

(800) 647–5227) is located on the plaza 

level of the Nassif Building at the DOT 

street address stated in the ADDRESSES

section. Comments will be available in 

the AD docket shortly after the Docket 

Management System receives them. 

Discussion 

The FAA has examined the 

underlying safety issues involved in fuel 

tank explosions on several large 

transport airplanes, including the 

adequacy of existing regulations, the 

service history of airplanes subject to 

those regulations, and existing 

maintenance practices for fuel tank 

systems. As a result of those findings, 

we issued a regulation titled ‘‘Transport 

Airplane Fuel Tank System Design 

Review, Flammability Reduction and 

Maintenance and Inspection 


cprice-sewell on PRODPC61 with PROPOSALS
19824 Federal Register / Vol. 72, No. 76 / Friday, April 20, 2007 / Proposed Rules 

Requirements’’ (66 FR 23086, May 7, 

2001). In addition to new airworthiness 

standards for transport airplanes and 

new maintenance requirements, this 

rule included Special Federal Aviation 

Regulation No. 88 (‘‘SFAR 88,’’

Amendment 21–78, and subsequent 

Amendments 21–82 and 21–83). 

Among other actions, SFAR 88 

requires certain type design (i.e., type 

certificate (TC) and supplemental type 

certificate (STC)) holders to substantiate 

that their fuel tank systems can prevent 

ignition sources in the fuel tanks. This 

requirement applies to type design 

holders for large turbine-powered 

transport airplanes and for subsequent 

modifications to those airplanes. It 

requires them to perform design reviews 

and to develop design changes and 

maintenance procedures if their designs 

do not meet the new fuel tank safety 

standards. As explained in the preamble 

to the rule, we intended to adopt 

airworthiness directives to mandate any 

changes found necessary to address 

unsafe conditions identified as a result 

of these reviews. 

In evaluating these design reviews, we 

have established four criteria intended 

to define the unsafe conditions 

associated with fuel tank systems that 

require corrective actions. The 

percentage of operating time during 

which fuel tanks are exposed to 

flammable conditions is one of these 

criteria. The other three criteria address 

the failure types under evaluation: 

Single failures, single failures in 

combination with a latent condition(s), 

and in-service failure experience. For all 

four criteria, the evaluations included 

consideration of previous actions taken 

that may mitigate the need for further 

action. 

The Joint Aviation Authorities (JAA) 

has issued a regulation that is similar to 

SFAR 88. (The JAA is an associated 

body of the European Civil Aviation 

Conference (ECAC) representing the 

civil aviation regulatory authorities of a 

number of European States who have 

agreed to co-operate in developing and 

implementing common safety regulatory 

standards and procedures.) Under this 

regulation, the JAA stated that all 

members of the ECAC that hold type 

certificates for transport category 

airplanes are required to conduct a 

design review against explosion risks. 

We have determined that the actions 

identified in this proposed AD are 

necessary to reduce the potential of 

ignition sources inside fuel tanks, 

which, in combination with flammable 

fuel vapors, could result in fuel tank 

explosions and consequent loss of the 

airplane. 

The European Aviation Safety Agency 

(EASA), which is the Technical Agent 

for the Member States of the European 

Community, notified us that an unsafe 

condition may exist on all Airbus Model 

A300 series airplanes. The EASA 

advises that Airbus has issued new fuel 

airworthiness limitations (FALs) to 

address failure conditions for which an 

unacceptable probability of ignition risk 

could exist if specific tasks or practices 

or both are not performed in accordance 

with the manufacturer’s requirements. 

The new FALs are intended to satisfy 

the JAA’s Interim Policy of Fuel Tank 

Safety and SFAR 88 requirements. 

Relevant Service Information 

Airbus has issued A300 Fuel 

Airworthiness Limitations, Document 

95A.1928/05, Issue 1, dated December 

19, 2005 (approved by the EASA on 

March 13, 2006). Section 1, 

‘‘Maintenance/Inspection Tasks,’’ of 

Document 95A.1928/05 describes 

certain FAL inspections, which are 

periodic inspections of certain features 

for latent failures that could contribute 

to an ignition source. Section 2, 

‘‘Critical Design Configuration Control 

Limitations,’’ of Document 95A.1928/05 

identifies critical design configuration 

control limitations (CDCCLs). A CDCCL 

is a limitation requirement to preserve 

a critical ignition source prevention 

feature of the fuel tank system design 

that is necessary to prevent the 

occurrence of an unsafe condition. The 

purpose of a CDCCL is to provide 

instruction to retain the critical ignition 

source prevention feature during 

configuration change that may be 

caused by alterations, repairs, or 

maintenance actions. A CDCCL is not a 

periodic inspection. 

Accomplishing the actions specified 

in the service information is intended to 

adequately address the unsafe 

condition. The EASA mandated the 

service information and issued 

airworthiness directive 2006–0200, 

dated July 11, 2006, to ensure the 

continued airworthiness of these 

airplanes in the European Union. 

FAA’s Determination and Requirements 

of the Proposed AD 

This airplane model is manufactured 

in France and is type certificated for 

operation in the United States under the 

provisions of section 21.29 of the 

Federal Aviation Regulations (14 CFR 

21.29) and the applicable bilateral 

airworthiness agreement. As described 

in FAA Order 8100.14A, ‘‘Interim 

Procedures for Working with the 

European Community on Airworthiness 

Certification and Continued 

Airworthiness,’’ dated August 12, 2005, 

the EASA has kept the FAA informed of 

the situation described above. We have 

examined the EASA’s findings, 

evaluated all pertinent information, and 

determined that we need to issue an AD 

for airplanes of this type design that are 

certificated for operation in the United 

States. 

Therefore, we are proposing this AD, 

which would require revising the 

Airworthiness Limitations Section 

(ALS) of the Instructions for Continued 

Airworthiness to incorporate new 

limitations for fuel tank systems. 

Differences Between the Proposed AD 

and EASA Airworthiness Directive 

For airplanes that have exceeded 

34,000 total flight hours as of effective 

date of the EASA airworthiness 

directive 2006–0200, the EASA 

airworthiness directive states that Task 

28–18–00–03–1, ‘‘Operational check of 

lo-level/underfull/calibration sensors,’’

must be done within 6 years or 20,000 

flight hours after the effective date. This 

AD, however, would require 

accomplishing Task 28–18–00–03–1 at 

the later of the following compliance 

times: (1) Prior to the accumulation of 

40,000 total flight hours, or (2) within 

72 months or 20,000 flight hours after 

the effective date of this AD, whichever 

occurs first. The EASA is considering 

further rulemaking to implement this 

change in the compliance time. 

EASA airworthiness directive 2006–

0200 states that the defined intervals for 

the FALs have to be counted from the 

effective date of the EASA airworthiness 

directive. This proposed AD would 

instead start counting the first interval 

of the FALs from the later of the 

following compliance times: (1) The 

effective date of this AD, or (2) the date 

of issuance of the original French 

standard airworthiness certificate or the 

date of issuance of the original French 

export certificate of airworthiness. The 

EASA also is considering further 

rulemaking to implement this change in 

the compliance time. 

Clarification of Service Information 

EASA airworthiness directive 2006–

0200 requires adherence to certain 

maintenance and inspection tasks in 

‘‘* * * Airbus ALS Part 5, Fuel 

Airworthiness Limitations as defined in 

document A300 Fuel Airworthiness 

Limitations, 95A.1928/05 at Issue 1 

* * * ’’. However, Airbus has not yet 

published a document titled, ‘‘Airbus 

ALS Part 5, Fuel Airworthiness 

Limitations,’’ for Model A300 series 

airplanes. This proposed AD instead 

refers only to Airbus A300 Fuel 

Airworthiness Limitations, Document 

95A.1928/05, Issue 1; the maintenance 


cprice-sewell on PRODPC61 with PROPOSALS
Federal Register / Vol. 72, No. 76 / Friday, April 20, 2007 / Proposed Rules 19825 

and inspections tasks are found in 

Section 1 of that document. 

Costs of Compliance 

This proposed AD would affect about 

30 airplanes of U.S. registry. The 

proposed actions would take about 2 

work hours per airplane, at an average 

labor rate of $80 per work hour. Based 

on these figures, the estimated cost of 

the proposed AD for U.S. operators is 

$4,800, or $160 per airplane. 

Authority for This Rulemaking 

Title 49 of the United States Code 

specifies the FAA’s authority to issue 

rules on aviation safety. Subtitle I, 

section 106, describes the authority of 

the FAA Administrator. Subtitle VII, 

Aviation Programs, describes in more 

detail the scope of the Agency’s 

authority. 

We are issuing this rulemaking under 

the authority described in subtitle VII, 

part A, subpart III, section 44701, 

‘‘General requirements.’’ Under that 

section, Congress charges the FAA with 

promoting safe flight of civil aircraft in 

air commerce by prescribing regulations 

for practices, methods, and procedures 

the Administrator finds necessary for 

safety in air commerce. This regulation 

is within the scope of that authority 

because it addresses an unsafe condition 

that is likely to exist or develop on 

products identified in this rulemaking 

action. 

Regulatory Findings 

We have determined that this 

proposed AD would not have federalism 

implications under Executive Order 

13132. This proposed AD would not 

have a substantial direct effect on the 

States, on the relationship between the 

national Government and the States, or 

on the distribution of power and 

responsibilities among the various 

levels of government. 

For the reasons discussed above, I 

certify that the proposed regulation: 

1. Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866; 

2. Is not a ‘‘significant rule’’ under the 

DOT Regulatory Policies and Procedures 

(44 FR 11034, February 26, 1979); and 

3. Will not have a significant 

economic impact, positive or negative, 

on a substantial number of small entities 

under the criteria of the Regulatory 

Flexibility Act. 

We prepared a regulatory evaluation 

of the estimated costs to comply with 

this proposed AD and placed it in the 

AD docket. See the ADDRESSES section 

for a location to examine the regulatory 

evaluation. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Safety. 

The Proposed Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA proposes to amend 14 CFR part 

39 as follows: 

PART 39—AIRWORTHINESS 

DIRECTIVES 

1. The authority citation for part 39 

continues to read as follows: 

Authority: 49 U.S.C. 106(g), 40113, 44701. 

§ 39.13 [Amended] 

2. The Federal Aviation 

Administration (FAA) amends § 39.13 

by adding the following new 

airworthiness directive (AD): 

Airbus: Docket No. FAA–2007–27927; 

Directorate Identifier 2006–NM–182-AD. 

Comments Due Date 

(a) The FAA must receive comments on 

this AD action by May 21, 2007. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to all Airbus Model 

A300 series airplanes, certificated in any 

category, except Airbus Model A300–600 

series airplanes. 

Note 1: This AD requires revisions to 

certain operator maintenance documents to 

include new inspections and critical design 

configuration control limitations (CDCCLs). 

Compliance with the operator maintenance 

documents is required by 14 CFR 91.403(c). 

For airplanes that have been previously 

modified, altered, or repaired in the areas 

addressed by these inspections and CDCCLs, 

the operator may not be able to accomplish 

the inspections and CDCCLs described in the 

revisions. In this situation, to comply with 14 

CFR 91.403(c), the operator must request 

approval for an alternative method of 

compliance according to paragraph (j) of this 

AD. The request should include a description 

of changes to the required inspections and 

CDCCLs that will preserve the critical 

ignition source prevention feature of the 

affected fuel system. 

Unsafe Condition 

(d) This AD results from fuel system 

reviews conducted by the manufacturer. We 

are issuing this AD to prevent potential of 

ignition sources inside fuel tanks, which, in 

combination with flammable fuel vapors 

caused by latent failures, alterations, repairs, 

or maintenance actions, could result in fuel 

tank explosions and consequent loss of the 

airplane. 

Compliance 

(e) You are responsible for having the 

actions required by this AD performed within 

the compliance times specified, unless the 

actions have already been done. 

Revise Airworthiness Limitations Section 

(ALS) to Incorporate Fuel Maintenance and 

Inspection Tasks 

(f) Within 3 months after the effective date 

of this AD, revise the ALS of the Instructions 

for Continued Airworthiness to incorporate 

Airbus A300 Fuel Airworthiness Limitations, 

Document 95A.1928/05, Issue 1, dated 

December 19, 2005 (approved by the 

European Aviation Safety Agency (EASA) on 

March 13, 2006), Section 1, ‘‘Maintenance/ 

Inspection Tasks.’’ For all tasks identified in 

Section 1 of Document 95A.1928/05, the 

initial compliance times start from the later 

of the times specified in paragraphs (f)(1) and 

(f)(2) of this AD, and the repetitive 

inspections must be accomplished at the 

interval specified in Section 1 of Document 

95A.1928/05, except as provided by 

paragraph (g) of this AD. 

(1) The effective date of this AD. 

(2) The date of issuance of the original 

French standard airworthiness certificate or 

the date of issuance of the original French 

export certificate of airworthiness. 

Initial Compliance Time for Task 28–18–00–

03–1 

(g) For Task 28–18–00–03–1, ‘‘Operational 

check of lo-level/underfull/calibration 

sensors,’’ identified in Section 1, 

‘‘Maintenance/Inspection Tasks,’’ of Airbus 

A300 Fuel Airworthiness Limitations, 

Document 95A.1928/05, Issue 1, dated 

December 19, 2005: The initial compliance 

time is the later of the times specified in 

paragraphs (g)(1) and (g)(2) of this AD. 

Thereafter, Task 28–18–00–03–1 must be 

accomplished at the repetitive interval 

specified in Section 1 of Document 

95A.1928/05. 

(1) Prior to the accumulation of 40,000 

total flight hours. 

(2) Within 72 months or 20,000 flight hours 

after the effective date of this AD, whichever 

occurs first. 

Revise ALS to Incorporate CDCCLs 

(h) Within 12 months after the effective 

date of this AD, revise the ALS of the 

Instructions for Continued Airworthiness to 

incorporate Airbus A300 Fuel Airworthiness 

Limitations, Document 95A.1928/05, Issue 1, 

dated December 19, 2005 (approved by the 

EASA on March 13, 2006), Section 2, 

‘‘Critical Design Configuration Control 

Limitations.’’

No Alternative Inspections, Inspection 

Intervals, or CDCCLs 

(i) Except as provided by paragraph (j) of 

this AD: After accomplishing the actions 

specified in paragraphs (f) and (h) of this AD, 

no alternative inspections, inspection 

intervals, or CDCCLs may be used. 

Alternative Methods of Compliance 

(AMOCs) 

(j)(1) The Manager, International Branch, 

ANM–116, Transport Airplane Directorate, 

FAA, has the authority to approve AMOCs 

for this AD, if requested in accordance with 

the procedures found in 14 CFR 39.19. 

(2) To request a different method of 

compliance or a different compliance time 

for this AD, follow the procedures in 14 CFR 


cprice-sewell on PRODPC61 with PROPOSALS
19826 Federal Register / Vol. 72, No. 76 / Friday, April 20, 2007 / Proposed Rules 

39.19. Before using any approved AMOC on 

any airplane to which the AMOC applies, 

notify your appropriate principal inspector 

(PI) in the FAA Flight Standards District 

Office (FSDO), or lacking a PI, your local 

FSDO. 

Related Information 

(k) EASA airworthiness directive 2006–

0200, dated July 11, 2006, also addresses the 

subject of this AD. 

Issued in Renton, Washington, on April 11, 

2007. 

Stephen P. Boyd, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. E7–7517 Filed 4–19–07; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2007–27925; Directorate 

Identifier 2006–NM–183–AD] 

RIN 2120–AA64 

Airworthiness Directives; Airbus Model 

A310 Series Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for all 

Airbus Model A310 series airplanes. 

This proposed AD would require 

revising the Airworthiness Limitations 

Section of the Instructions for 

Continued Airworthiness to incorporate 

new limitations for fuel tank systems. 

This proposed AD results from fuel 

system reviews conducted by the 

manufacturer. We are proposing this AD 

to prevent the potential of ignition 

sources inside fuel tanks, which, in 

combination with flammable fuel vapors 

caused by latent failures, alterations, 

repairs, or maintenance actions, could 

result in fuel tank explosions and 

consequent loss of the airplane. 

DATES: We must receive comments on 

this proposed AD by May 21, 2007. 

ADDRESSES: Use one of the following 

addresses to submit comments on this 

proposed AD. 

• DOT Docket Web site: Go to 

http://dms.dot.gov and follow the 

instructions for sending your comments 

electronically. 

• Government-wide rulemaking Web 

site: Go to http://www.regulations.gov 

and follow the instructions for sending 

your comments electronically. 

• Mail: Docket Management Facility, 

U.S. Department of Transportation, 400 

Seventh Street, SW., Nassif Building, 

Room PL–401, Washington, DC 20590. 

• Fax: (202) 493–2251. 

• Hand Delivery: Room PL–401 on 

the plaza level of the Nassif Building, 

400 Seventh Street, SW., Washington, 

DC, between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

Contact Airbus, 1 Rond Point Maurice 

Bellonte, 31707 Blagnac Cedex, France, 

for service information identified in this 

proposed AD. 

FOR FURTHER INFORMATION CONTACT: Tom 

Stafford, Aerospace Engineer, 

International Branch, ANM–116, FAA, 

Transport Airplane Directorate, 1601 

Lind Avenue, SW., Renton, Washington 

98057–3356; telephone (425) 227–1622; 

fax (425) 227–1149. 

SUPPLEMENTARY INFORMATION:

Comments Invited 

We invite you to submit any relevant 

written data, views, or arguments 

regarding this proposed AD. Send your 

comments to an address listed in the 

ADDRESSES section. Include the docket 

number ‘‘FAA–2007–27925; Directorate 

Identifier 2006–NM–183–AD’’ at the 

beginning of your comments. We 

specifically invite comments on the 

overall regulatory, economic, 

environmental, and energy aspects of 

the proposed AD. We will consider all 

comments received by the closing date 

and may amend the proposed AD in 

light of those comments. 

We will post all comments we 

receive, without change, to http:// 

dms.dot.gov, including any personal 

information you provide. We will also 

post a report summarizing each 

substantive verbal contact with FAA 

personnel concerning this proposed AD. 

Using the search function of that Web 

site, anyone can find and read the 

comments in any of our dockets, 

including the name of the individual 

who sent the comment (or signed the 

comment on behalf of an association, 

business, labor union, etc.). You may 

review the DOT’s complete Privacy Act 

Statement in the Federal Register 

published on April 11, 2000 (65 FR 

19477–78), or you may visit http:// 

dms.dot.gov. 

Examining the Docket 

You may examine the AD docket on 

the Internet at http://dms.dot.gov, or in 

person at the Docket Management 

Facility office between 9 a.m. and 

5 p.m., Monday through Friday, except 

Federal holidays. The Docket 

Management Facility office (telephone 

(800) 647–5227) is located on the plaza 

level of the Nassif Building at the DOT 

street address stated in the ADDRESSES

section. Comments will be available in 

the AD docket shortly after the Docket 

Management System receives them. 

Discussion 

The FAA has examined the 

underlying safety issues involved in fuel 

tank explosions on several large 

transport airplanes, including the 

adequacy of existing regulations, the 

service history of airplanes subject to 

those regulations, and existing 

maintenance practices for fuel tank 

systems. As a result of those findings, 

we issued a regulation titled ‘‘Transport 

Airplane Fuel Tank System Design 

Review, Flammability Reduction and 

Maintenance and Inspection 

Requirements’’ (66 FR 23086, May 7, 

2001). In addition to new airworthiness 

standards for transport airplanes and 

new maintenance requirements, this 

rule included Special Federal Aviation 

Regulation No. 88 (‘‘SFAR 88,’’

Amendment 21–78, and subsequent 

Amendments 21–82 and 21–83). 

Among other actions, SFAR 88 

requires certain type design (i.e., type 

certificate (TC) and supplemental type 

certificate (STC)) holders to substantiate 

that their fuel tank systems can prevent 

ignition sources in the fuel tanks. This 

requirement applies to type design 

holders for large turbine-powered 

transport airplanes and for subsequent 

modifications to those airplanes. It 

requires them to perform design reviews 

and to develop design changes and 

maintenance procedures if their designs 

do not meet the new fuel tank safety 

standards. As explained in the preamble 

to the rule, we intended to adopt 

airworthiness directives to mandate any 

changes found necessary to address 

unsafe conditions identified as a result 

of these reviews. 

In evaluating these design reviews, we 

have established four criteria intended 

to define the unsafe conditions 

associated with fuel tank systems that 

require corrective actions. The 

percentage of operating time during 

which fuel tanks are exposed to 

flammable conditions is one of these 

criteria. The other three criteria address 

the failure types under evaluation: 

single failures, single failures in 

combination with a latent condition(s), 

and in-service failure experience. For all 

four criteria, the evaluations included 

consideration of previous actions taken 

that may mitigate the need for further 

action. 

The Joint Aviation Authorities (JAA) 

has issued a regulation that is similar to 

SFAR 88. (The JAA is an associated 

body of the European Civil Aviation 


cprice-sewell on PRODPC61 with PROPOSALS